Seattle to Shatter Record 90s Streak, But Northwest Heat Relief Is Ahead (FORECAST)

Jon Erdman
Published: July 5,2015

It may not be quite as hot as last weekend in some areas, however, this torrid heat wave in the Northwest, now in its second week, will continue for awhile this week.
There is some relief on the way, however. Just not over the next few days.

Heat Alerts

Current Temperatures

Seattle is likely to shatter its record streak of 90-degree-plus highs -- five straight days in 1981 and 1941 -- early this week. Boise, Idaho, tied its all-time record streak of 100-degree-plus highs on July 4, a string of nine straight days.
June and even a few all-time record highs were shattered in parts of the interior Northwest, northern Rockies and Great Basin early on in this heat wave.
(MORE: Northwest Heat Wave By the Numbers)
We've seen numerous daily record highs the last few days, and more are expected the next several days in Oregon, Washington and northern Idaho.
Here are some of the recent daily records that have been set:
- Medford, Oregon, tied its daily record Saturday (103 degrees).
- Wenatchee, Washington, set a daily record Saturday (105 degrees).
- Seattle set daily record highs on Thursday (93 degrees), Friday (92 degrees) and Saturday (92 degrees).
- Kalispell, Montana set daily record highs on Friday (95 degrees) and Saturday (99 degrees).
- Warfield, British Columbia set a daily record Saturday, reaching 38.2 degrees Celsius (100.8 degrees Fahrenheit).
The culprit in this hot setup is a blocking pattern aloft, known as a "Rex block" that is keeping cooler Pacific air from pushing much farther inland from the typically cooler areas near the immediate Northwest coast.

Heat Relief Is Ahead

Highs well into the 90s and some triple-digit heat are expected in many lower-elevation locations from Idaho to Oregon and Washington much of this week. This is where temperatures will be 5-20 degrees above average the next several days.

Forecast Highs

Epicenter of the Heat

This doesn't just include the interior Northwest, which has seared under the worst of both the magnitude and persistence of the heat, but also the Pacific Northwest west of the Cascades. Some of these areas are unaccustomed to longer stretches of 90-degree-plus heat.
Heat advisories have been posted for portions of the Northwest including Seattle, Portland and Eugene.
Compared to what the region is used to, evening and overnight temperatures will be slow to drop, bottoming out in the upper 60s and 70s in the hottest locations.
There is hope on the horizon, with the top taken off temperatures late in the week as upper-atmospheric blocking over the eastern Pacific Ocean finally gives way just enough.
This should knock temperatures in both Seattle and Portland into the upper 70s or 80s Friday into next weekend. Temperatures in the searing interior Northwest should also cool off into the upper 80s or low 90s by next weekend.
In addition, the northern Rockies have benefited from a cold front over the weekend. Unfortunately, they will become hot yet again later in the week, and will remain generally warmer than average into next weekend.
(FORECASTS: Seattle | Portland | Boise | Salt Lake City)
The hot, dry weather is also causing a high fire danger, as drought conditions have worsened over the Northwest and northern Rockies in the spring.
(MORE: Latest on Western Wildfires)
In mid-May, Washington Gov. Jay Inslee issued a statewide drought emergency, and spring runoff from winter's paltry snowpack was expected to be the least in 64 years.
Seattle has seen only 8 days with measurable rain since May 1, one-third the average number of such days, according to NWS-Seattle. Their last rainfall of one-half inch or more was almost three months ago, on April 13. Portland, Oregon, has gone over a month without measurable rainfall, last occurring on June 3.
One of the biggest factors in heat wave deaths is not only the magnitude, but also the longevity of the heat. Take safety precautions against the heat.
Those playing or working outdoors, as well as those without access to air conditioning, will face an elevated risk of heat-related illness. According to the U.S. Energy Information Administration, 25 percent of homes, apartments, condos in the states of Idaho, Montana, Utah and Wyoming do not have air conditioning.
Remember to never leave kids or pets unattended in cars and drink more water than usual. Wear light-colored clothing and keep your head and body cooler with a hat. Take frequent rest breaks in shaded or air-conditioned environments.
(MORE: Earth's Record Year? | How Hot is Too Hot?)
Meteorologist Chris Dolce contributed to this report.

MORE: Heat Waves of the Past (PHOTOS)